1 // SPDX-License-Identifier: GPL-2.0-or-later
31 	struct hwrng rng;  member
38 static int stm32_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)  in stm32_rng_read()  argument
41 	    container_of(rng, struct stm32_rng_private, rng);  in stm32_rng_read()
45 	pm_runtime_get_sync((struct device *) priv->rng.priv);  in stm32_rng_read()
48 		sr = readl_relaxed(priv->base + RNG_SR);  in stm32_rng_read()
50 		/* care of initial delay time when enabling rng	*/  in stm32_rng_read()
52 			retval = readl_relaxed_poll_timeout_atomic(priv->base  in stm32_rng_read()
57 				dev_err((struct device *)priv->rng.priv,  in stm32_rng_read()
64 					"bad RNG status - %x\n", sr))  in stm32_rng_read()
65 				writel_relaxed(0, priv->base + RNG_SR);  in stm32_rng_read()
69 		*(u32 *)data = readl_relaxed(priv->base + RNG_DR);  in stm32_rng_read()
73 		max -= sizeof(u32);  in stm32_rng_read()
76 	pm_runtime_mark_last_busy((struct device *) priv->rng.priv);  in stm32_rng_read()
77 	pm_runtime_put_sync_autosuspend((struct device *) priv->rng.priv);  in stm32_rng_read()
79 	return retval || !wait ? retval : -EIO;  in stm32_rng_read()
82 static int stm32_rng_init(struct hwrng *rng)  in stm32_rng_init()  argument
85 	    container_of(rng, struct stm32_rng_private, rng);  in stm32_rng_init()
88 	err = clk_prepare_enable(priv->clk);  in stm32_rng_init()
92 	if (priv->ced)  in stm32_rng_init()
93 		writel_relaxed(RNG_CR_RNGEN, priv->base + RNG_CR);  in stm32_rng_init()
96 			       priv->base + RNG_CR);  in stm32_rng_init()
99 	writel_relaxed(0, priv->base + RNG_SR);  in stm32_rng_init()
104 static void stm32_rng_cleanup(struct hwrng *rng)  in stm32_rng_cleanup()  argument
107 	    container_of(rng, struct stm32_rng_private, rng);  in stm32_rng_cleanup()
109 	writel_relaxed(0, priv->base + RNG_CR);  in stm32_rng_cleanup()
110 	clk_disable_unprepare(priv->clk);  in stm32_rng_cleanup()
115 	struct device *dev = &ofdev->dev;  in stm32_rng_probe()
116 	struct device_node *np = ofdev->dev.of_node;  in stm32_rng_probe()
123 		return -ENOMEM;  in stm32_rng_probe()
129 	priv->base = devm_ioremap_resource(dev, &res);  in stm32_rng_probe()
130 	if (IS_ERR(priv->base))  in stm32_rng_probe()
131 		return PTR_ERR(priv->base);  in stm32_rng_probe()
133 	priv->clk = devm_clk_get(&ofdev->dev, NULL);  in stm32_rng_probe()
134 	if (IS_ERR(priv->clk))  in stm32_rng_probe()
135 		return PTR_ERR(priv->clk);  in stm32_rng_probe()
137 	priv->rst = devm_reset_control_get(&ofdev->dev, NULL);  in stm32_rng_probe()
138 	if (!IS_ERR(priv->rst)) {  in stm32_rng_probe()
139 		reset_control_assert(priv->rst);  in stm32_rng_probe()
141 		reset_control_deassert(priv->rst);  in stm32_rng_probe()
144 	priv->ced = of_property_read_bool(np, "clock-error-detect");  in stm32_rng_probe()
148 	priv->rng.name = dev_driver_string(dev);  in stm32_rng_probe()
150 	priv->rng.init = stm32_rng_init;  in stm32_rng_probe()
151 	priv->rng.cleanup = stm32_rng_cleanup;  in stm32_rng_probe()
153 	priv->rng.read = stm32_rng_read;  in stm32_rng_probe()
154 	priv->rng.priv = (unsigned long) dev;  in stm32_rng_probe()
155 	priv->rng.quality = 900;  in stm32_rng_probe()
161 	return devm_hwrng_register(dev, &priv->rng);  in stm32_rng_probe()
166 	pm_runtime_disable(&ofdev->dev);  in stm32_rng_remove()
176 	stm32_rng_cleanup(&priv->rng);  in stm32_rng_runtime_suspend()
185 	return stm32_rng_init(&priv->rng);  in stm32_rng_runtime_resume()
199 		.compatible = "st,stm32-rng",
207 		.name = "stm32-rng",
219 MODULE_DESCRIPTION("STMicroelectronics STM32 RNG device driver");